Method and apparatus particularly applicable to measurements of the calorific value of combustible gases



June 24, 1930. PACKARD 1,767,771 METHOD AND APPARATUS PARTICULARLY APPLICABLE TO MEASUREMENTS OF THE GALORIF'IC VALUE OF COMBUSTIBLE GASES Filed Jan. 21- 1921 Patented June 24, 1930 UNITED STATES,

PATENT OFFICE HORACE N. rncxaan, or urrwauxnn, wrscousm, ASSIGNOR, BY mnszm ASSIGN- mmzrs, 'ro CUTLER-HAMMER, me, A CORPORATION or DELAWARE METHOD AND APPARATUS PARTICULARLY APPLICABLE TO MEASUREMENTS TH CALOBIFIC VALUE OF COMBUSTIBLE GASES Application filed January 21, 1921. Serial m.-'43a,s54.

This invention relates to ametho'd and apparatus particularly applicable to meas urements of the calorific value of combustible gases or other chemically reactive agents although certain features thereof have other advantageous applications.

' In my prior patent No. 1,625,277, dated April 19, 1927, are disclosed a method and apparatus wherein constant volumetric proportions of test gas, combustion air and cooling air are delivered under like temperature, pressure and saturation conditions to a device for. effecting combustion of the gas and transfer of the heat so liberated to the cooling air, the consequent temperature rise of the latter being indicated, whereby any variation in heating value of the test gas causes a corresponding proportional change in the indicated temperature rise of such cooling air and the latter comprises a measure of the former.

The present invention has among its objects that of providing another method of efiecting the foregoing and other results with certain advantages over such former method.

A more specific object is that of providing such a method wherein the necessity of certain corrections of the results of the former method is obviated.

Another object is that, ofproviding such a therefor.

Another object is that of providing such I a method possessin characteristics which render the same particularly applicable to regulation for constant or other desired temperature efiects, either with or without definite ascertainment or indication of values.

Another object is that of providing simple and efficient form of apparatus for performance of such method.

Another object is that of providing an apparatus for carrying out theaforestated method, wherein compensation is made for possible errors due to temperature variations tending to influence the results thereof,

Other objects and advantages will hereinafter appear.

The accompanying drawing illustrates schematically and diagrammatically a proposed form of such apparatus and the same will now be described, it being understood that such apparatus may be modified in numerous ways within the scope of the appended claims.

Following the disclosure of said prior patent, the test gas and combustion air are supplied to a suitable burner for combustion thereof, the cooling fluid being separately supplied to an associated heat exchange device for absorption of the heat so liberated sired indication. Also as in said patent, all of said fluids are supplied under like conditions of temperature, pressure and saturation and in definite proportions by volume. Moreover, the construction and arrangement of the burner and heat exchange device are such as to maintain like temperature of the incoming combustion fluids and the escaping combustion products while preventing intermingling of the cooling fluid with any of the other fluids, whereby the temperature rise of said cooling fluid is a true measure of the total heating value of the test gas.

As distinguished from the former method, it is now proposed to provide for varying the and the consequent temperature use of said cooling fluid is utilized in eflecting the de-.

proportions of the supplied test gas and air to compensate for variations in heating value of the gas and responsive to variations in temperature rise of the cooling fluid, whereby such temperature rise is maintained substantially constant and the values" of the variations so efiected in the proportioning of said fluids constitute a measure of the heating value of such test gas. Also the former method and apparatus have been modified in Ways to be hereinafter described to eliminate possible errors including those dueto temperature variation which are independent of the combustion.

' Referring to thedrawing, the same illustrates a burner and associated heat'exchange device 1, having the aforedescribed structural and functional characteristics and p displacement meter structures located within a common liquid seal comprising water or other liquid to be, maintained at a substantially constant level within a. tank 8. Said pumps are further adapted to be power driven by a suitable motor 9. The power connection of pumps 6 and 7 to said motor is such that said pumps are driven at like speeds and hence maintain a constant proportionality of the volumes of fluids delivered thereby. The drive of the gas pump 5, on the other hand, includes a speed changing device such as the opposed cone pulleys 10, 11 and the shiftable idler 12 illustrated, whereby the proportion of gas to air delivered may be varied; Obviously, if desired, the gas pum 5 might be driven at a speed constant witli respect to the motor speed and the s eed of the air pumps 6 and 7 varied wit reference thereto. Test gas is admitted to the pump 5 through a conduit 13 at a pressure equal to the intake pressure of the pumps 6 and 7. In practice a pressure regulating device 14 provides for delivery of the gas to the pump intake at atmospheric pressure, whereas the air pumps ,6 and 7 which draw from the interior of tank 8 are also supplied at atmospheric pressure by means of a passage 15 which connects the interior of said tank with the outer air.

Said pressure reducing device 14 preferably comprises a barrier 16 located within vthe conduit 13 and'provided with a reduced opening 17, and an open ended branch pipe 18 connected with said conduit on the pump side of said barrier. In operation the barrier 16 serves to restrict the flow of gas therebeyond to a value which is able to-escape through the pipe 18 without raising the pressure upon the pump side of said barrier above atmos heric ressure, whereas the outward flow 0 gas tl irough said pipe 18 effectively prevents induction of air into the pump. The gas so issuing from the pipe 18 is ordinarily ignited and burned to avoid pollution of the surrounding air. Such continuous efllux of gas in appreciable quantities from said tube further serves to insure that the test gas drawn into the pump constitutes a true sample of the main supply undergoing test. Also the gas in passing through the pump is caused to attain the temperature of the sealing liquid within the tank 8, to which temperature the fluids handled by the pumps 6 and 7 are also subjected, all of said pumped fluids being also subjected to like intimate contact with such sealing liquid and hence becoming saturated therewith at such common temperature.

Thus provision is made for supplying the air and gas to the device 1 under like conditions of temperature, pressure and satura tion and for maintaining a constant proportioning of the delivered volumes of combustion air and cooling air, while providing for relative variation of the proportion by volume of the delivered gas, the proportioning of such fluids, moreover, being unaffected by variations in speed of motor 9.

Hence, assuming such proportioning of the three fluids as to efiect complete chemical union of the two reactive gases and complete absorption by the cooling fluid of the heat so liberated, it is apparent that any variation in heating value of the gas will effect a'corresponding and proportional variation in the consequent temperature rise of said cooling fluid. Also if the relative rate of supply of gas and air be varied, by shifting the idler 12, to compensate for such variation in heating value of the gas, the character and degree of such shiftingconstitutes an accurate measure of the character and degree of such variation, whereas such variation in rate of supply serves to maintain the proportions suitable for complete combustion and absorption as aforementioned.

For example, assuming that'for a given sample of gas and a given setting of the idler 12 the cooling air shows a temperature rise of 10, such temperature rise will obtain even though the speed of motor 9 be doubled, such change serving merely to double the rates of delivery of all three fluids without changingthe proportions thereof.

On the other hand assuming the heating value of the sample of gas to be reduced to one half of that formerly assumed, the relative speed of the several pumps as determinedby the position of the idler remaining unchanged, the temperature rise of said cooling fluid will be reduced to 5. 'Again assume adjustment of the idler 12 to increase the relative speed of gaspump 5 sufiiciently to restore the temperature rise of the cooling fluid to its former value it is apparent that the character and amount of such shifting may be indicated and the indicating means calibrated to show the heating value of the gas continuously in B. t. u. or according to any desired or preferred system of units. Y

Resistance thermometers 19 and 20 are ar-" ranged in a known manner with reference to the device 1 for measuring respectively the temperature of the cooling fluid before and after the heat exchange. These resistance thermometers are utilized in a Wheatstone bridge to control a galvanometer 21 having associated with its needle 22 a switch 23, having an operating solenoid 24, which serves, in conjunction with a contact drum In practice the motor 9, switch 23 and the solenoids of ratcheting device 28 are supplied from a suitable source L, L of either direct or alternating current. The movement of said ratchetingmechanism is preferably communicated through suitable gearing to a screw shaft 30, the latter to "cooperate with a non-rotative nut 31 upon which the idler 12 is rotatably carried, whereby operation of said ratcheting mechanism in either direction serves to shift said idler axiall of its associated cones, to a proportiona degree and in a corresponding direction, to similarly vary the speed ratio of the drive throughsaid cones and hence of the pump 5 to pumps 6 and 7.

The structure and manner of co-operation of the switch 23, the contact drum 25 and the ratcheting device 28 are clear from the drawing, the same being described at length in my aforementioned patent and elsewhere, and as no specific novelty of such individual elements per se is claimed herein, the same will be described only in conjunction with the other elements of the device.

The resistance thermometers are respectively connected to opposite terminals of the galvanometer and to one side of a D. C. supply circuit L, L through a balancing rheostat 32, while resistances-33 and 34 are respectively connected to opposite terminals of the galvanometer and to the opposite side of said D. C. circuit to complete the Wheatstone bridge.

Also a so-called temperature difference resistance 35 is located preferably within the tank 8 and arranged to be connected in series with the resistance thermometer 19 for a purpose to be hereinafter described, a switch 36 providing for completion of the Wheatstone bridge connections either inelusive or exclusive ofsaid resistance 35.

Thus assuming such apportionment of the resistance of rheostat 32 between the two sides of the Wheatstone bridge as to effect a balance of the latter having reference to the difier'ence in temperature of the resistance thermometers 19 and 20 efiected by heating of the cooling fluid incident to combastion of test gas of a givenheating'value,

and also assuming that the marker of the recorder be' properly positioned with respect to a reference point or line upon the chart to correspond with such given heating value of the testgas, any variation of such heating value and consequent variation in temperature rise of coolin air will cause the Wheatstone bridge to ecome unbalanced. Thereupon the galvanometer needle becomes deflected in a corresponding direction and to a degree determined by the degree of such Variation and the switch 23 acting in conjunction with the contact drum '25is adapted to effect energization of the appropriate operating solenoid of theratcheting mechamsm 28 for operation of said ratcheting mechanism in a direction and to a degree again determined by the character and degree of variation of the heatin value of the test gas. The ratcheting mec anism in turn functions to shift the idler 12 in a direct-ion and to a degree suitable for varying the relative speed of the gas pump 5 to cause the latter to supply gas either more rapidly or less rapidly asmay be required to restore the preselected difference in temperature between the resistance thermometers and hence -to restore the balance of the Wheatstone bridge. Also the ratcheting mechanism, in so functioning, serves to shift the marker of the recorder to indicatethe character and value of the 'proportioning action thus effected, which in turn is a measure of the heating Value of the gas, it being remembered that the temperature rise of the cooling fluid varies in direct proportion to the changes in such heating value. Thus the apparatus automatically compensates for variations in temperature difference of the resistance thermometers to thereby maintain number of degrees. Moreover, such-ditference in the resistance rise of the two thermometers increases as the lower or base temperature is increased, although the ac tual difference in temperature of the two thermometers be maintained constant, it being remembered that in the present case such base temperature is the temperature of the cooling fluid entering the device 1, which temperature is, as'stated, the .same as that obtaining within the tank 8. Thus due to such cause an increase in tank temperature over that obtaining at the time of balancing the Wheatstone bridge will tend to cause the recorder to indicate too high a heating value of the gas, and upon creases.

On the other hand the specific heat of the cooling fluid, if air, rises upon increase of its content of vapor of the sealing liquid, which content in turn likewise increases with a rise in temperature of said sealing liquid. Thus for a higher tank temperature the cooling fluid requires more heat to raise its temperature a given number of degrees than is required at lower tank temperatures, which cause tends to introduce into the regulation and recording action an error similar but opposite to the thermometer error.

Also the heating value of a given volume of the test as decreases upon increase in the degree 0% dilution thereof with vaporof the sealing li uid, that is to say, upon 1ncrease in tan temperature, the resultant error being cumulative with that due to the aforementioned variation in specific heat of the cooling fluid.

Thus in the present instance, the tendencies to error due to variation in vapor content of the gasand the cooling fluid tend to ofiset that due to variation in temperature-resistance coefficient of the resistance of special provisions, strictl thermometers, but obviously, in the absence 7 accurate results will be obtained only i the opposing tendencies to error are of equal value, which condition will seldom arise in practice.

However, the tem erature difference resistance 35, provide with circuit'connections as described and located preferably within the tank 8 .for subjection to the temperature conditions there obtaining, may be designed and calibrated to .compensate for all of the aforementioned tendencies to error, or more properly for the differential of the opposing tendencies.

Said temperature difference resistance is preferably composed of resistive material, such as a suitable combination of nickel, copper and manganin, or certain of such substances, so proportioned and combined that the temperature resistance coefiicient of said resistance is adapted to vary, under varying temperature conditions in a manner to compensate for the corresponding variations in temperature-resistance coefficient of theresistance thermometers. Ordinarily the temperature difference resistance may be so designed that its temperature-re sistance coefficient varies in the same sense as that of the resistance thermometers but at a lesser rate. However, under certain conditions,.;as where relatively high temperatures are involved, it may be necessary or desirable to employ a material such that the temperature-resistance coefiicient of said resistance is adapted to var in a sense which is the opposite of that o .the coefiicient of the resistance thermometers, or to em loy an arrangement to produce a similar e ect.

signed to correspond to the temperature difference which it is desired to maintain between the resistance thermometers, for which reason said resistance has been designatedas a temperature difference resistance. In the operation of the device inclusive of said resistance the Wheatstone bridge is first balanced in the usual manner, in the absence of heat in the device 1 and said resistance being excluded from circuit. Upon inclusion of said resistance in series with the resistance thermometer 19 the brid e becomes'unbalanced to a degree correspond ing to the resistive value 0 said resistance under the existing temperature conditions. Thus torestore the balance of the bridge, the fiuid pumps are operated and the reaction fluids ignited tosupply to the cooling fluid sufficient heat,to increase the resistance of the thermometer 20 by an amount equivalent to that of said resistance whereupon the apparatus is adapted to function as aforedescribed. V

If at any time the temperature of the various fluids, as determined by that of the sealing liquid rises above its value at the time of balancin the Wheatstone bridge, the indications efiected by the device will tend to vary from the true values due to the three causes aforediscussed. However, the

temperature difl'erence resistance, if prop erly designed and calibrated, serves to overcome such tendencies.

It is also (possible by suitable selection of material an design, to so modify the temperature-resistance coefiicient of one or both of the resistance thermometers as to adapt the same toeffect the aforedescribed compensating action without the aid of a separate temperature difierence resistance, where as any of the foregoing expedients ma if .70 Moreover, the value of said resistance 1s dedesired, be utilized for securerrent of e ects difierent from or additional to those stated.

Since the recorder 29 indicates, in effect, merely the speed ratio of the gas and air pumps, it is apparent that any one of a number of known devices may be subjected to' control in accordance with the value of such ratio and'so utilized to provide distant indication for recording of the heating value of the test gas.

While the foregoing descri tion ,relates chiefly to determination of the eating value of a combustible fluid, it is to be understood that the instant method and apparatus are equally applicable to other reactions of the same or different agents and involving either liberation or absorption of heat.

Obviously by slight modification of the ply regulation of the various fluids that is required to maintain a constant flame temperature and to regulate for maintaining such constant flame temperature either with or without indication of the heating value of the gas.

Again assuming location of the resistance thermometers respectively within the stream of the combustion fluids prior to combustion thereof and within the stream of combustion products, the combustion fluids being proportioned as described, the device may be adapted to perform regulating and indicat- 4 ing functions similar to those performed by the preferred form of calorimeter.

The afore-indicated adaptability of the method and apparatus to regulation of the supply of the combustion fluids for securing and maintaining a desired calorific effect is inherent in the instant principle'of calorimetry which includes regulation and indication or determination of the degree and character of the regulation effected.

What I claim as new and desire to secure by Letters Patent is:

1. The method of calorimetry which com prises effecting a chemical reaction involving a given agent definitely proportioned relatively to another substance and effecting predetermined variations in the relative propor tions of such agent and other substance automatically in response to variations in certain calorific effects of the reaction.

2. The method of calorimetry which comprises effecting a chemical reaction involving a given agent definitely proportioned relatively to another substance and effecting predetermined variations in the relative proportions of such agent and other substance automatically in response to variations in value of the difference between a temperature which is a direct function of the reaction and a temperature independent of the reaction. I

3. The method of calorimetry which comprises effecting a chemical reaction involving a given agent to obtain a temperature which is a direct function of the reaction and utilizing the relation of successive values of the difference between such temperature and a tem era-ture independent of the reaction for e ecting automatic definite variation of.

the proportion of such agent relative to another substance. 4, The method in calorimetry of quantitatively proportioning a chemical agent and another substance according to the calorific effect of a chemical reaction involving such agent, which comprises effecting such chemical reaction to obtain a temperature which is a direct function thereof and definitel controlling the relative-proportions of suc agent and other substance automatically in response to variations in value of the difference between such temperature and a term perature independent of the reaction, to

thereby maintain substantial uniformity ofsuccessive values of such temperature difference. a

5. The method which comprises effecting a chemical reaction involving a given agent, subjecting a separate fluid substance to the calorific effect of such reaction for efiecting a heat exchange and varying the relative proportions of such agent and other substance automatically in response to variations in such calorific eflect to obtain a given relation of certain successive effects of-the heat exchange; V v 6; The method which comprises effecting a chemical reaction involving a given agent, subjecting a separate fluid substance to the calorific effect of the reaction, proportioning such agent and substance for obtaining a given temperature change of the latter as a result of the reaction, and varying the relative proportions of such agent and other substance automatically in response to varia tions in such calorific effect to maintain substantially constant the temperature change to which such substance is subjected.

v 7. The method of proportioning a chemical agent and a separate fluidsubstance ac-' 'the relative proportion of another of such agents automatically in response to -variations in value of the difference between a temperature which is a function of the reaction and a temperature independent of the reaction. I

9. The method which comprises effecting a chemical reaction involving given agents, and definitely varying the proportion of certain of such agents relatively to other of the same automatically in response to'variations in value of successive calorific effects of such reaction to maintain substantially constant the value of such calorific eflects. 10. The method of measurement of the heating value of a combustible fluid which comprises efiecting combustion of such fluid with another fluid, efiecting a flow of cooling fluid in a heat exchanging relation with the products of combustion, proportioning the supply of certain of the fluids to main tain the resultant temperature rise of the cooling fluid substantia ly constant and utilizing the effected variations in proportionality as a basis of suchmeasurement.

11. The method of ascertaining the heating value of a combustible fluid which comprises effecting combustion of a quantity of such fluid in heat exchan ing relation with a quantity of a different aid and regulating the quantitative proportioning of such fluids to maintain a substantially constant effect of the resultant heat exchange.

12. The method of ascertaining the heat- 7 ing value of a combustible fluid which comprises supplying under like conditions of tc-m erature, pressure and saturation, test flui air to be mixed therewith and a cooling fluid, burning the mixture of test fluid and air in a heat exchanging relation to said cooling fluid, proportioning the suppl of said fluids to maintain a given effect 0 the resultant heat exchange and utilizing the character and extent of such proportioning action for determination of the heating value of the test fluid. p

13. In apparatus for supplying fluids or other substances and varying the supply of one substance relative to another according to a calorific effect ofa chemical reaction involving certain of such substances, the combination with means to supply such substances and to vary the quantitative proportionality thereof, of control means for the former means responsive to variations in the difference between a temperature which is a function of the reaction and a temperature which is independent of the reaction.

14. In apparatus for supplying fluids or other substances and varying the supply of one substance relative to another according toa calorific effect of a chemical reaction involving certain of such substances, the combination with means to supply such substances and to vary the quantitative pr0portionality thereof, of control means for theformer means, subjected to influence in accordance with the relation of successive values of the difference between a temperature which is a function of the reaction and a temperature which is independent of the reaction, for maintaining substantially a given relation of such successive values.

15. In apparatus for supplying fluids or I other substances and varying the supply of one substance relative to another according to a calorific effect of a chemical reaction involving certain of such substances, the combination with means to supply such substances and to vary the quantitative proportionality thereof, of control means for the former means, subjected to influence in ac cordance with the relation of successive values of the difference between va temperature whichis a function of the reaction and a temperature which is independent of the reaction, for maintaining substantially a constant value of such temperature difference. v

16. In apparatus for supplying fluids or other substances, varying the supply of one substance relative to another according to a calorific effect of a chemicalreaction involving certain of such substances and ascertaining the value of certain of such substances for producing such effect, the combination with means to supply such substances and to vary the quantitative proportionality thereof, of means to act upon said former means in accordance with variations in the difference between a tem erature which is a func-v tion of such calorific effect and a tempera-' ture which is independent of such eflect, for causing said former means to maintain substantially a given relation of successive values of such temperature difli'erence, and means utilizing the degree and character of the action of-said latter means for ascertaining such value of said certain of such substances.

17. Apparatus comprising the combination with means to supply in definite proportions agents for a given chemical reaction, of associated means operable automatically in accordance with variations in a calorific effect of the reaction to act upon said former means for regulating the supply and proportionality of such agents to maintain substantially constant successive values of such calorific effect of the reaction.

18. The combination with means to supply an agent for a given chemical reaction thereof, of means, including a definitely proportioned medium, subjected to influence in accordance with the relation of successive values of a calorific effect of such reaction to act upon said former means for regulating the supply of said agent to maintain substantially a constant value of such effect,

said agent and said medium in accordance with the relation. of successive calorific effects, and -means' utilizing the degree and character of operation of-said proportioning means for indicating the value of said agent for producing such effect.

20. The combination with means to supply, in definite proportions, an agent for a given reaction thereof and a separate medium to be subjected to a heat exchange which is a function of the calorific efi'ectof such reaction, of means subjected to influence in accordance with the relation of similar successive calorific effects, for proportioning the supply of said agent and said medium to maintain substantially a constant calorific effect. 7

21. The combination with means to supply, in definite proportions, a plurality of agents for a given chemical reaction thereof, and a medium to be subjected to a heat exchange which is a function of the calorific eflect of such reaction, of associated means to act upon said former means for proportioning the supply of certain of said agents and said medium to maintain substantially a constant calorific effect.

such calorific effect are maintained substantially constant.

23. The combination with means to supply, in definite proportions, a plurality of agents for a chemical reaction thereof, of associated means to act upon said former means, in accordance with the relation of successive values of a calorific effect of such reaction for maintaining substantially a constant value for such effect, and means controllable by said latter means for indicating the value of certain of such agents for producing such effect.

24:. Apparatus for determining the heating value of a combustible fluid conprisin in combination means to supply said flui for combustion and also a diiferent fluid at relatively regulable rates and under like conditions of temperature, pressure and saturation, means to influence'said former means for proportioning the supply of said fluids to maintain a given relation of successive values of a calorific effect of the combustion and means controllable by said proportioning means for indicating the heating value of said former fluid.

25. Apparatus for determining the heating value of a combustible fluid, comprising in combination, means to supply said fluid .for combustion and also a different fluid,

at relatively regulable rates, means, includ ing resistance thermometers to be connected in a Wheatstone bridge to influence said 22. The combination with means former means for proportioning the supply of said fluids to maintain a given relation of successive values of a calorific effect of the combustion, and mean's controllable by said proportioning means for indicating'the heatin value of said former fluid.

26. pparatus for determining the heating value of a combustible fluid, comprising in combination, means to supply said fluid,

a different fluid and a cooling fluid, at relatively regulable rates and under like conditions of temperature, pressure and saturation, for combustion of said former fluids and absorption of the liberated heat by said cooling fluid, means for proportioning the o supply of said 'fluids to maintain a given relation of successive values of the resultant temperature rise of said cooling fluid. and means controllable by said proportioning means for indicating the character and cooling fluid, means, including resistance thermometers to be connected in a Wheatstone bridge, to influence said former means for proportioning the supply of said fluids to maintain a given relation of successive values of the resultant temperature rise of said cooling fluid and means controllable by said proportioning means for indicating the heating value of said first fluid.

28. In apparatus for 'ascertainin the heating value of a combustible flui the 05 combination with means for efl'ectin combustion of a regulable quantity 0 such fluid, of resistance thermometers to be connected in a Wheatstone bridge and subjected to temperatures whose difference is a function of calorific effect of such combustion, temperature difference resistance to be connected in circuit with certain of said resistance thermometers and subjected to a tem erature which is independent of the com ustion, and means controllable by the VVheatstone bridge for indicating the heating value of the fluid.

29. In apparatus for ascertainin' the heating value of a. combustible fluid combination with means for efl'eotin combustion of a regulable quantity 0 such fluid, of a Wheatstone bridge having certain of its elements adapted to change their resistance under variable temperature con.-

ditions and subjected to temperatures whose difference is a function of a calorific eflect of such combustion, said elements being constructed and arranged to maintain substantially a given relation of their respecdiflerent fluid and a cooling fluid, at relathe 120 I i controllable by said W tive temperature-resistance characteristics throughout the working range, and means eatstone bridge for indicating the heating value of the fluid.

' 30. The method which comprises the step of normally efieoting a flow of combustible fluid and a flow of fluid to support combustion thereof in redetermined -proportions, ascertaining t e total heatingvalue per unit volumeof said combustible fluid and varying the proportionality of sai flows of fluids automatically in response to variations in such total heating value.

31. The method which com rises effecting separate flows of fluids one 0 which is combustible and the other of which is adapted to support combustion thereof, normally maintaining a predetermined proportionality between the volumetric rates of flowof said fluids, ascertaining the instantaneous calorific value per unit volume of said combustible fluid, and definitely varying the volumetric pro rtionality of said flows of fluids automatically in response to variations in such calorific value.

In witness whereof, I have hereunto subscribed my name.

HORACE N. liACKAB-D, 

